Recent years, a touch detection device capable of detecting an external proximity object, which is referred to as so-called a touch panel has attracted an attention. The touch panel is mounted or integrated on a display device such as a liquid crystal display device. In this way, a liquid crystal display device where a touch panel is mounted or integrated on a display device, i.e., a liquid crystal display device with a touch detection function makes various kinds of button images displayed on the display device, and the touch panel detects for an external object to have been close to the button image. Thereby, it makes it possible to use a touch panel as a device for information inputting with the touch panel as a substitute of a usual mechanical button. Since such a liquid crystal display device with a touch detection function does not necessarily need a device for information inputting like a keyboard or a mouse, the usage is in an expanding trend also in a portable information terminal etc., like a mobile phone other than a computer.
As a detection method of a touch detection device, there exist several methods such as an optical type, a resistance type and an electrostatic capacitance type. Among these, a touch detection device of the electrostatic capacitance type has a comparatively simple structure, and is low in the power consumption, and therefore, has been used for a portable information terminal etc. In Japanese Patent Laid-Open Patent Publication No. 2011-233018 and Japanese Patent Laid-Open Patent Publication No. 2012-047807, a touch detection device of an electrostatic capacitance type has been described.